The invention pertains to the field of creating a field emission display using an array of fibers and an orthogonal array of emitter electrodes. The invention further relates to using carbon nanotubes as the electron emitters. The invention further relates to using a metal-insulator-metal cathode for the electron emission electrode.
One of the largest problems plaguing the FED industry is the ability to create support structures to maintain a millimeter-sized gap between the high-voltage plane and the emitter plane under hard vacuum. These support structures must be strong enough to support the vacuum pressures and small enough not to block the emission region in the display. The support structures must also be an insulting material, such that an arc does not form from the emitter plane to the high-voltage plane. One very unique method of forming the structure within a FED is to combine the support structure with the phosphor layer, as discussed in U.S. Pat. No. 5,984,747. This patent discloses using a fiber array containing high voltage electrode and phosphor layer arrayed orthogonal to a glass plate with orthogonal diamond emitter electrodes deposited on the surface of a glass plate. To address the FED disclosed in U.S. Pat. No. 5,984,747 the high voltage would have to be modulated. The electronics needed to switch the high voltage fast enough to address every pixel in a reasonably sized display is presently impossible to construct. Therefore, a new field emission structure is needed that separates the addressing of the electron emission from the high voltage used to accelerate the emitted electrons toward the phosphor layer.
Another pitfall with fabricating large FEDs is creating the electron emitters. Electron emitters are traditionally made using Spindt tips, U.S. Pat. No. 3,665,241. These field emitter tips are fabricated on a silicon wafer using a costly multilevel photolithography process. Diamond has been shown to yield a low electron emission coefficient, however no one has been able to demonstrate a technique to address the film using a low voltage addressing technique. Another very interesting emitter material was discovered by S. Iijma Nature, Vol. 354, 1991, pp. 56-58 is carbon nanotubes. Because of the shape of the nanotube structures they have very low field emission voltages as first shown by W. A. de Heer, et al. in Science, Vol. 270, 1995, pp 1179-1180. Using nanotubes as the emitting layer could be very advantageous because they could be used to fabricate very large displays. However, like its diamond emitter counterpart no one has demonstrated a low-voltage addressing scheme using these materials. It is the purpose of the present invention to disclose such a low voltage addressing method for using both the diamond and nanotube emitters.
Another field emitter material disclosed within is the use of fibers with a metal-insulator-metal, MIM, cathode emitter. MIMs cathode emitters have been previously disclosed.
Briefly stated, the invention pertains to the field of constructing a field emission display using an array of fibers and an orthogonal array of emitter electrodes. Each fiber in the fiber array contains an extraction electrode, spacer, a high voltage electrode and a phosphor layer. The array of emitter electrodes consists of carbon nanotube emitters attached to conductive electrodes. The emitter electrodes are separated using non-conductive fibers. A getter material in the form of a wire is placed within the array of emitter electrodes to maintain a high vacuum within the display.
Another aspect of the invention involves using a metal-insulator-metal cathode as the electron emission source for the display.